The invention relates to a tilt drive for metallurgical vessels, particularly useful as a steel-mill converter tilt drive, with its large sprocket wheel arranged, within a casing, non-rotatively on the rocker pin supporting the casing, with reduction gears arranged by the large sprocket wheel, said reduction gears dragging at a torsion around the secondary shaft, and with the non-rotative pinions on the secondary shafts of said reduction gears always meshing with the large sprocket wheel as well as with brakes which may be switched on and off.
Such drives have been designed for several years as gears riding on the converter rocker pin (also designated as so-called flying drives). The essential characteristic of this type tilt drive is the transmission of the drive force from one or a plurality of stationary electric motors onto two or more pinions meshing to the large sprocket wheel. The division of the drive force into several partial drive forces leads to control problems of the electric motors because the driven pinions must each transmit their partial drive force synchronously with the large sprocket wheel.
The transmission of partial drive forces occurs during the dynamic as well as during the static operation of the drive. The static drive signifies the support of forces caused by the unbalancing and vibration during a tilt position of the vessel which does not vary over time, in which position the brakes of the tilt drive are switched on.
The dynamic as well as the static operation of the tilt drive also leads to uncontrollable motions behind the brakes during the drive flow. These motions are mainly caused by the manufacturing tolerances of the large sprocket wheel and the pinions as well as of the connected reduction gears, couplings and similar elements. Also, particularly in the dynamic operation, with the brakes switched off, the play between the teeth of the sprocket wheels and couplings, including those in the reduction gears, adds to the motions.
Vibrations in the static operation result during the oxidation period from the reactions in the metal bath. These vibrations are transmitted to the brick lining and wall structure of the converter vessel. In the event that the converter vessel is supported on a bearing ring which is arranged by means of the rocker pin in a tilt frame, the vibrations are transmitted by the support elements between the converter wall structure and bearing ring and by the bearing ring to the rocker pin and, finally, to the rocker pin/large sprocket wheel combination and to the pinions which transmit the drive force to the rocker pin/large sprocket wheel combination. The vibrations cause damage particularly at the point where the teeth of the large sprocket wheel mesh with the pinion (DE-AS No. 26 58 885).
As indicated in the literature on static operation, pitching motions up to (.+-.) 50 mm occur at the crucible apertures.
In the dynamic operation, vibrations occur which are caused by the play of teeth at the large sprocket wheel at the pinion, and the play of teeth between the sprocket wheels of the reduction gear. A synchronous drive of the pinions is indeed aimed for; however, a drive of this type is realizable only with great difficulty, if at all. The reason lies in the respective different angles of rotation of the electric motors per time unit. Regulating all the individual electric motors is not feasible because the technical expenditure required does not justify the result. In order to achieve a synchronous run of the pinions, the electric motor would have to produce a uniform torque.
Controlling the individual electric motors as a function of the angular positions of the respective pinions of the other individual drives is also expensive and enlarges the proportion of electric equipment of a tilt drive for metallurgical vessels.
Controlling the individual electric motors as a function of one or several other electric motors is complicated and expensive, and an appropriate adaptation of the torques of the two pinions may only be approximated.
The object of the present invention is to protect the tilt drive for metallurgical vessels in the dynamic operation by mechanical means from its own vibrations, and further to design the drive mechanism such that it may also be protected in static operation from outside vibrations.